Expression of the nuclear gene TaF sub(A)d is under mitochondrial retrograde regulation in anthers of male sterile wheat plants with timopheevii cytoplasm

• Published in: Journal of experimental botany 2008-04, Vol.59 (6), p.1375-1381
• Main Authors: Xu, Pei, Yang, Yuwen, Zhang, Zhengzhi, Chen, Weihua, Zhang, Caiqin, Zhang, Lixia, Zou, Sixiang, Ma, Zhengqiang
• Format: Article
• Language: English
• Subjects: Allium cepa; Triticum aestivum
• ISSN: 0022-0957; 1460-2431

Alterations of mitochondrial-encoded subunits of the F sub(o)F sub(1)-ATP synthase are frequently associated with cytoplasmic male sterility (CMS) in plants; however, little is known about the relationship of the nuclear encoded subunits of this enzyme with CMS. In the present study, the full cDNA of the gene TaF sub(A)d that encodes the putative F sub(A)d subunit of the F sub(o)F sub(1)-ATP synthase was isolated from the wheat (Triticum aestivum) fertility restorer '2114' for timopheevii cytoplasm-based CMS. The deduced 238 amino acid polypeptide is highly similar to its counterparts in dicots and other monocots but has low homology to its mammalian equivalents. TaF sub(A)d is a single copy gene in wheat and maps to the short arm of the group 6 chromosomes. Transient expression of the TaF sub(A)d-GFP fusion in onion epidermal cells demonstrated TaF sub(A)d's mitochondrial location. TaF sub(A)d was expressed abundantly in stem, leaf, anther, and ovary tissues of 2114. Nevertheless, its expression was repressed in anthers of CMS plants with timopheevii cytoplasm. Genic male sterility did not affect its expression in anthers. The expression of the nuclear gene encoding the 20 kDa subunit of F sub(o) was down-regulated in a manner similar to TaF sub(A)d in the T-CMS anthers while that of genes encoding the 6 kDa subunit of F sub(o) and the gamma subunit of F sub(1) was unaffected. These observations implied that TaF sub(A)d is under mitochondrial retrograde regulation in the anthers of CMS plants with timopheevii cytoplasm.